K 10
svn:author
V 3
jhb
K 8
svn:date
V 27
2020-01-17T19:01:59.536071Z
K 7
svn:log
V 418
Save and restore floating point registers in get/set_mcontext().

arm64 and riscv were only saving and restoring floating point
registers for sendsig() and sys_sigreturn(), but not for getcontext(),
setcontext(), and swapcontext().

While here, remove an always-false check for uap being NULL from
sys_sigreturn().

Reviewed by:	br, mhorne
Sponsored by:	DARPA
Differential Revision:	https://reviews.freebsd.org/D23218

END